A hollow tube has one end closed and the other end open. A stationary sound wave with the minimum possible frequency, $820\,\text{Hz}$, is set up in the tube. The speed of sound in air is $330\,\text{m s}^{-1}$. How long is the tube?
- A$10\,\text{cm}$
- B$20\,\text{cm}$
- C$40\,\text{cm}$
- D$160\,\text{cm}$